This invention relates to the field of integrated circuits. More particularly, this invention relates to communication using interconnect circuitry connected between one or more master units and one or more slave units of an integrated circuit.
It is known to provide integrated circuits with interconnect circuitry connecting master units to slave units. An example of such interconnect circuitry are those built in accordance with the AMBA AXI interface designed by ARM Limited of Cambridge, England.
It is known within the field of data processing systems to utilise token-based communication. Master units that are to generate a communication transaction must possess a token before they are able to issue that communication transaction. This provides a mechanism for dividing the communication resources between different masters. Within such systems it is typical that a number of tokens are allocated to each master in advance and stored and managed within the masters and the slaves. As a way of balancing the utilisation of the communication channels between different masters, such that a high priority master will gain more access to the communication channels than a low priority master, it is known to issue more tokens to the high priority master than to the low priority master. While this is one way of balancing the access to the communication channels, it disadvantageously increases the number of tokens present within the system which must be stored and managed. This produces a disadvantageous increase in the complexity and cost of the system.